Cuba's leading dissident, Oswaldo Paya, threw down a new challenge to Fidel Castro's government yesterday by delivering a petition with more than 14,000 signatures to the country's parliament to demand a referendum for sweeping changes in the socialist system.

"The Varela Project lives," Mr Paya told reporters before visiting the National Assembly to hand in the petition, which followed up a similar initiative last year. "The campaign continues across the country."

Mr Paya was accompanied by his wife, Ofelia, and another Varela Project volunteer as he carried the large box filled with petition forms up the concrete stairs of the government building. He said the petition held 14,384 signatures, up from the first batch of 11,400 signatures collected last year. Mr Paya stayed inside for about 40 minutes before reporting that the petition had been accepted by the government.

There was no immediate response to the demand from the authorities. Assembly members rejected the first package of signatures, describing the changes sought as unconstitutional.

Earlier, Mr Paya had told a news conference that government repression of project workers had increased in recent weeks, with dozens of people who had circulated the petition being picked up for questioning. Although he complained of harassment, he said that none of them had been formally charged.

The signature-gathering drive is seen as the biggest home-grown, non-violent effort in four decades to push for reforms to Cuba's one-party system. The first petition was delivered days before the former US president Jimmy Carter visited Cuba in May last year when, during an uncensored speech broadcast live across the island, he told Cubans of the campaign.

The petitions propose a referendum asking voters if they favour civil liberties such as freedom of speech and assembly, and an amnesty for political prisoners.

Named after Felix Varela, a Cuban independence hero and Catholic priest, the signature drive was discussed by rights activists in Havana as early as 1996. But not until 2001 did volunteers begin collecting signatures in earnest. (AP)